Just kidding, though only for the 2nd part. Your renter module picks the cheapest possible offers automatically, but there's some randomization built in such that more expensive hosts may also be picked from time to time.

I have not figured out yet why the devs are doing it that way, and I don't care enough to go ask them - but if you're interested in these questions, then the Slack channel may be a better venue to get in touch with the devs on algorithm questions.